Improvement in propelling mechanisms



anni effin.

eCHRISTIAN'SHAltPS, 0F PHILADELPHIA, PENNSYLVANIA.

Letters Patent No. 109,458, dated November 22,1870.

IMPROVEMENT IN PROPELLlNGyMECHANISMS.

The Schedule referred to in Vthese Letters Patent and um of the lame.

'1, GHBIsTrAN Simens, of Philadelphia, county of Philadelphia., State of Pennsylvania, haveinvented certain Propelling Mechanism for Vessels, of which the following is a specification.

I l Nature and Object of the'Inrcnti/on.

My invention relates to improvcmentsiu the pro peiling mechanism for which Let-ters Patent were granted to me on the 25th day ot' May, 1869, also on the 21st of September, 1869, the main feature of the said lpatented propelling mechanism consist-ing of a non-submcrged wheel, or a wheel with a-liinited dip, and having inclined blades; and secured to a'n inclined shaft, and partaking of the 'character of apaddle-whecl as well as of a screw propeller. j l

My present improvements, which are based -'upon the result of repeated and costly experiments, consist in the combination of an inclined shaft with a propeller having blades which are sections of differential screwthreads, as explained hereafter, the shaft of the propeller being, in all cases, above the water-line.

The object of this feature of my invent-ion is to obtain a propeller-wheel of large diameter, which shall have the best effect in shallow water, shall clear the latter readily, and shall cause but little swell.

My invention further consists of a two-bladed propeller, arranged on an inclined shaft in respect to the centerline ofthe enginc'and crank in the manner described hereafter, so that there may be but little resistance to the passage of the crank over its deadcenters, and so that the engine may be uniform in'its action, and its lpower exerted through the most advantageous medium, and in proportion to the duty which it has to perform. v.

Also, of a peculiar propeller, described hereafter, made with the view to economy and facility, both as regards original construction, and repairing in case of accidents. Y

The main object` of my improvements has been to obtain a propeller applicable to light-draught vessels for navigating narrow land shallow rivers, creeks', &c., and also as an auxiliary propelling medium for schooners and other light-draught vessels, the sails of which are of little use in narrow and tortnous creeks.

Description of the Accompai-zying Drawing.

Figure 1 is' sectional view of thc stern of a vessel with my propelling mechanism.

Fgure 2, a plan view.v

Figures 3, 4, 5, 6, 7, and 8, views illustrating the peculiar construction of the propeller.

Figure 9, a diagram illustrating one feature of my invention.

Generai Besoriptzon.

A represents the projecting stern of a vessel; B, the propeller-shaft;V

1), the steam-cylinder of the driving-engine; E, the propeller;

F, the rudder; and

G, the keel.

lhe propeller-shalt B is placed atan angle in re-- spect to a longitudinal midship `vline, x and .I' have ascertained by repeated experiments that the Abest results may be obtained when this angle is between fifteen and twenty degrees in respect to that line.

' The propeller has two blades, a and a', each of which is the section of a screwtlrcad, in the present instance of a differential screw-thread; that is to say, the inc linaticn of `the blade at its extreme outer edge, y, is

Ymore abrupt-in respect to the center line of the shaft than it is at its junctiom'y, with the hub, or, in other words, the pitch of the thread decreases iii extent from the hub outward. It should be understood, however, in thc outset, that. the blade need not be a section of a differential screw-tln'ead under all circumstances, a subject which, will be referred to hereafter. K p

One of the prominent features of my invention is the relative positions of the two-bladed propeller and center line of the engine and crank. This arrangement will be best observed by referring tothe diagram,.iig. 9, in which t represents the center line of the engine,

-situatcd at light angles to the center line w ot' the propeller when the crank is at half-stroke, and one blade is at its greatest depth in the water. p

1f the central line of the cylinder is horizontal, as shown, and passes through the center ofthe propellershaft, the central line zo of the propeller lwill'be coincident with a line drawn through the` center of the shaft and center' of the crank-pin; hence the crank will pass over its dead-center easily, for, when the crank is at citherof its dead-centers, the propeller-blades, or

thevgreater portion of the sanie, will be out of water, while the crank will be irrthe best position for transferring the power of the engine t0 the propeller when one of its blades is in the water and the greatest power is required. The result of this arrangement must be the easy passage of the crank over its deadcenters, uniformity in thc speed of the engine, andthe transmission ofthe power of the 'same to the best advantage, and iu accordance with the duty it has to perform.

,Another important feature of my invention is the peculiar construction of the propeller and the mode of securing the same to thc shaft, as illustrated in figs. 3, 4, 5, 6, 7,'and S.

The ,blades are cast separately', and are. secured together and to the shaft at the hub l). p

The shaft has two keys o1' feathers, el d, one adapted to a recess in the half-hub of one blade, and the other to a like recess in thc half-hub of the other blade, and the two halthubs are connected together and confined to the shafts by bolts passing through lugs ff.

As a further security, however, the hub of the propeller has,'at cach end, a tapering projection adapted to the tapering interior of a ring, 71, and the two rings are connected together by bolts, t' t, figs. land 2, on tightening Athe nut-sof ,which the rings'will be drawn toward each other, and the two half-hubs of the blades will be securely confined to each other and to the shaft. 'Iwo advantages are obtained by this feature ot' my invention; rst,.but one pattern is required from which both blades can be molded; and second, if a blade be broken, that blade only, and not thc entire wheel, has to'be discarded. to make way for a new blade.

In carrying out my invention it is preferable,- in most eases, that the blade should bc a section of a differential screw-thread.

My lpropelling mechanism has been designed i'or small light-draught vessels for the navigation` ot' shallow rivers, creeks, Sto. Repeatedand long-continued experiments have convinced me that for such vessels a propeller with the center ot' its inclined shaf't above the water-line and blades forming sections of screwthreads forms the most a 7ailable propelling medium, as the blades clear themselves from the water readily and cause but little swell.

f I may remark here that the experimental vessel, which I have vbuilt'aud repeatedly tested, is seventyiive feetin length, has sixteen feet beam, and a draught of three feet, and has a single engine with a cylinder fourteen inches in diameter and fourteen inches stroke, the pressure of steam being about seventy-five pounds per square inch; that the propeller is eight feet in diameter and has a dip of three feet, the propeller-shaft being arranged atan angle ot' seventeen degrees in respect to the central midship line. ot' the vessel, and each of the two blades being a sect-ion of a differential screw-thread. The propeller made about one hundred revolutions per minute, and the average speed ot thel vessel was about fourteen miles per hour. I give these dimensions and particulars as successful results were obtained by the vessel in question, not because theyl should be adhered to exactly under all circumstances, t'or 'vessels of different sizes, draught, and power, may require different dimensions of propeller-sl and blades, and different inclinations of the blades.

My invention may be applied with advantage as an auxiliary propelling medium to schooners and other sailing Vessels, especially suoli as have to navigate tortuous rivers and creeks. where sails are of little use,

but where a propeller would be of the greatest aid, the propeller being simply adjusted to a horizontal position, clear ofthe water, when sails alone are used.

Then my mechanism is used as au auxiliary propelling medium, I use two blades only, and arrange the rudder as shown in iig. 1; but when used as the sole propelling medium of a vessel, I arrange the rudder astcrn of the propeller, which may have more than two blades.

In carrying out my invention, a propeller with simp le flat inclined blades would not serve .the desired purpose. As remarked above, the blades must be sections of a screw-thread.

I am aware that such propellers vhave been heretofore used, but they'have been submerged and placed on shafts parallel with the keel, whereas my propeller, with its screw-blades, has a limited dip in the water and is secured to an inclined shaft, and it is these three features in combina-tion, namely, a wheel of large diameter andy having a limited dip, blades forming sections of screw-threads, and an inclined propeller-shaft, by which the successful results have been attained, and which constitutes one feature ot` my invention. v-

I have also remarked above thata dilierential screwblade is to bc preferred, but a regular screw-blade may be used in a wheel of' large diameter and very slight dip.

Claims.-

1. The combination of an inclined shaft with a propeller having bladesy which are sections of diterential screw-threads, decreasing in the extent ot' pitch from the hub outward, when the whole is so applied to a vessel that the said shaft shall be above the water-line.

2. A two-bladed propeller, arranged ou an inclined shaft in respect to the center lin'c ot' the crank, asset forth.

v3. A propeller, consisting of two separate blades, secured together and to the'shaft by rings hh and bolts z' t applied to the hub, substantially as described.

In'testimony whereof, I have signedpmy nanieto this speciieationin` the presence ot' two subscribing witnesses.

CHRISTIAN SHARPS.

Witnesses:

WM. A. STEEL, FRANK B. Ricnanns.

engine and 

